83 replies to this topic

[Zilch]

Virtually all AR fans should be interested in what Roy had to say about those concerts, since they relate to the real-world quality of the AR-3 speakers used in the demos. I bracketed that section in pencil marks in the draft when I first read it years ago.

Indeed, in which we learn that the concerts were even further "refined" than we previously knew.

["Eddie was a great showman...." ]

[Zilch]

Spin, counterspin.

[I thought my words were inoffensively chosen, actually.... ]

[Shacky]

To me Allison's comments on the live versus recorded demonstrations reinforces rather than questions their validity as Zilch seems to be sarcastically intimating.

The recordings moved the mikes around in anechoic setting to capture the sound the instrument radiates - vs. reproducing the sound of a concert hall. This makes perfect sense so that the playback in the concert setting won't doubly reproduce the enviornmental factors.

And he's honest about the treble boost. Give me a break. Can't we forgive a little treble boost from an era without the advantage of computers?

Thanks so much, Howard, for posting!

[speaker dave]

No need to waste new words. I'll just repeat what I said last August when this debate was last in full bloom:

Live vs. recorded demos are interesting but I'm not sure what the prove. Certainly, AR and others are to be commended for the effort needed to record a string quartet or drum set carefully and anechoically. The speakers would have to replicate the full dynamic range and be neutral enough not to reveal a shift in frequency balance. On the other hand, the speakers are placed as surrogate instruments and don't have to create a stereo soundfield. Most of the demos have been done in large music venues (in concert halls) so the hall will automatically carry the burden of creating a "realistic soundfield".

Since every well done demo of this kind, including the first by Edison, has had listeners leaving with the same comments we really have to question whether they provide proof of superiority of the speakers used. I know the Edison Diamond Disc players are considered among the best of their kind (of acoustical gramophone), but I doubt that any of us today would be fooled into believing they were live music rather than reproduced. They did set the basics of the live vs. recorded demo: record the musician anechoically (sing directly into the recording horn), choose the source carefully to match the limitations of the gramophone (voice only), play back in an appropriate acoustic space for the performance so that the system is offloaded of the need to create a realistic soundspace.

I've heard a few of my larger speaker designs (KEF KM1) playing back music in a large auditorium and they gave a totally different (and most impressive) presentation aided by a large natural acoustic. Is it possible that speakers are much better than we give them credit for, but the process of recording and reproducing a real soundfield, especially in a home living room, is actually the limitation?

As to Toole dismissing the issue of LvR. He should have gone farther. He should have realised that music reproduction had been perfected (as proven by the demonstrations) and found another line of work. Why continue on refining the science of designing and testing audio gear when clearly perfection had been achieved, perhaps even many decades earlier??

“The ear could not tell when it was listening to the phonograph alone, and when to actual voice and reproduction together. Only the eye could discover the truth by noting when the singer’s mouth was opened or closed.” The Edison 1916 demonstration to “musically cultured and musically critical”

David

[genek]

Why continue on refining the science of designing and testing audio gear when clearly perfection had been achieved, perhaps even many decades earlier??

As the "state of the art" progresses, the ability of listeners to discriminate recorded from live should also progress and they should become harder to fool. So perhaps an audience of today's most educated listeners might have a different result. Assuming, that is, that they haven't all switched over to systems with little cube speakers and iPod docks.

Modern testing technology should do a much better job of verifying product compliance to design goals than at any time in the past. The question is, what is the design goal? Is it based on what is required to create a credible semblance of an original, live performance, what is required to fit the results of listener preference comparisons of different products without comparison to a live performance, or just what is required to meet someone's theoretical model? Is anyone in audio design conducting listener testing of any audio gear - not just speakers - to gauge its ability to reproduce a live performance, or is everything now based on "accurate" reproduction of what is actually in the recording, even if it's a bad recording?

[Shacky]

Didn't Wharfedale also do a LvR demonstration? Thought I remember reading about it maybe even at Carnegie Hall?

I just finished restoring a pair of W70D MK II's. Though they won't replace my AR's they pair nicely with my tube amp. And where AR's may have been reticent in highs Wharfedale seems a tad reticent in bass. So I bet they had bass turned up a notch.

[Zilch]

And of course, if somebody did manage to successfully pull off another LvR series guys like me would say, hey, glad you people finally caught up to what Villchur did four decades ago!

Can't lose with that one; there's no way to improve upon perfection. I'm sure Edison said the same.

FACT is, just about any quality loudspeaker could do as well, as Allison has himself affirmed, yet we have only this contrived stunt remaining as evidence of the alleged enduring superiority of long-since outmoded design.

[This and market share, which standing is today enjoyed by Bose, in full testament of undisputable excellence.... ]

[genek]

Didn't Wharfedale also do a LvR demonstration? Thought I remember reading about it maybe even at Carnegie Hall?

Yes, in the 50's. According to published accounts, musicians were recorded as they played for the audience and then the recordings were played back to demonstrate how Wharfedale speakers reproduced the performance. Since the recordings were made in the hall, they weren't source-matched to anechoic originals so the audience would have been treated to a double dose of hall acoustics, but from the description of the demos, they weren't being asked to try to guess which was which.

What I was wondering was whether anyone is doing LvR comparisons today, if not publicly then privately as part of the development process.

[Zilch]

Yes, in the 50's. According to published accounts, musicians were recorded as they played for the audience and then the recordings were played back to demonstrate how Wharfedale speakers reproduced the performance. Since the recordings were made in the hall, they weren't source-matched to anechoic originals so the audience would have been treated to a double dose of hall acoustics, but from the description of the demos, they weren't being asked to try to guess which was which.

Recorded on stage, and close-miked, i.e., without "ambience" mics in the hall, there would be no "double dose;" the speakers would reproduce the direct sound of the instruments plus the stage reflections which, if played forward-facing to the hall, would likely provide a better match than anechoic recordings.

With the audience in place, there's not much hall reverb on stage.

['Til someone provides data proving that I just made this up.... ]

[genek]

Recorded on stage, and close-miced, i.e., without "ambience" mics in the hall, there would be no "double dose;" the speakers would reproduce the direct sound of the instruments plus the stage reflections which, if played forward-facing to the hall, would likely provide a better match than anechoic recordings.

With the audience in place, there's not much hall reverb on stage.

['Til someone provides data proving that I just made this up.... ]

Fair enough. Since the audience was apparently fully aware that they were listening to recordings, though, it is a demo of a different color. The photos of the stage also indicate that there were a lot more speakers than one pair. Would have been interesting to hear how it sounded.

[speaker dave]

Didn't Wharfedale also do a LvR demonstration? Thought I remember reading about it maybe even at Carnegie Hall?

Yes, I have a copy of a writeup from the Aug. 1955 Hi Fidelity.

"Very good but not versimiltude is, in fact, the over-all judgement for the session as a whole. Mr. Briggs had live harpsichord, piano, organ, and chorus on hand for test matching. The harpsichord in reproduction was excellent, just a bit short of perfect. The Wharfedale version of a piano was beautiful sound, but lacked the brightness and full sonority of a real Steinway heard a moment later, even in works calling for no great weight of piano tome. The organ matched well, when lighter registration was used, but no effort was made to match the speakers against a real thirty foot pipe."

This was in London's royal Festival Hall, a large (3000 people) hall known for its dead acoutics. Amazing that they could get the level from a number of Quad 15 watt amps.

The main event was a playback of a master tape of the BBC Symphony and chorus: "Certainly the effect was different from that of a chorus and orchestra on the stage, but the large masses of sound were full, spacious, and (the hardest thing of all) produced without apparent distortion or strain."

Briggs also played back a selection of commercial LPs.

While looking for this one I ran across another one from 1955 where 4000 seat Constitution Hall in D.C. was used. They actually recorded a symphony orchestra as it played and then played it back right after. The speakers were Jensen Imperials, a large horn loaded system. "The balance was rich and full. There was no doubt that it was recorded sound, but it was good recorded sound."

Reproducing an orchestra would, of course, require considerably more acoustic output.

Yet another one was the Bell Telephones Auditory Perspectives series which was famous for exploring 2 and 3 channel stereo playback in the early 1930s. In one demonstration they had an orchestra in an upstairs hall playing back downstairs in the primary concert hall. They also use phone lines to send the 3 channels from Philadelphia to Washington for another demonstration. The article talks about the you-are-there, they-are-here choice and also the need to record the orchestra fairly close, although they found the 3 channel reproduction better when they recorded from a little farther back. The playback system was a trio of 2way Western Electric theater speakers.

David

David

[speaker dave]

You noted that Edison recorded the human voice with some of his demos (and because of the nature of the pick-up horn those could have been reasonably anechoic), and I will myself note that I have done a lot of A/B comparing with various source materials, and while things like string quartets and dynamic symphony presentations will show up differences between speaker ensembles readily, the human voice nearly always sounded identical or close to identical from speaker to speaker (even those that sounded quite different with quartet music sources), and so what Edison did would have been no big deal even if the audience members who were impressed had been audio buffs.

Howard Ferstler

You're kidding right? We did a lot of testing with human voice at KEF. It was an extremely revealing test within its bandwidth (and widely acknowledged by BBC Engineering as most difficult to reproduce). We actually did some "Live vs. Recorded" with some of us recorded in the anechoic chamber. (B&K mic., Sony PCM F-1) One thing we found was that level matching typically meant listening at a much lower level than you would normally have guessed.

We spend our lives talking and listening to others (at least some of us listen) and we are very discerning about the naturalness of human voice, even of people we haven't met.

[kkantor]

You're kidding right? We did a lot of testing with human voice at KEF. It was an extremely revealing test within its bandwidth (and widely acknowledged by BBC Engineering as most difficult to reproduce). We actually did some "Live vs. Recorded" with some of us recorded in the anechoic chamber. (B&K mic., Sony PCM F-1) One thing we found was that level matching typically meant listening at a much lower level than you would normally have guessed.

We spend our lives talking and listening to others (at least some of us listen) and we are very discerning about the naturalness of human voice, even of people we haven't met.

No doubt, vocals are very difficult. Below is some press from the "Hi-Fi '97 Show," where NHT ran a constant live feed for listeners to directly compare live to recorded sound. (The was done with the assistance of the SF Symphony.) Although the reviewer below seems unaware of the this, harpsichord and electric guitar were also in the rotation. The vocals were, by far, the hardest to do. Every time the singer moved an inch or two, the tonality from the mic feed changed completely.

-k

(No doubt, it would have been easier if we had pre-recorded the musicians to allow us to control various factors. Playing back tapes of the feed was a very different experience than the real-time A/B.)


Other noteworthy pieces

NHT went through the trouble of actually assembling a live microphone feed from one room containing a musical artist (female singer) to a mixing console, into a Bryston amplifier, and NHT's own bass amps, and into their flagship 3.3s in the adjacent room. Lots of room treatment allowed a stable image of a woman's voice to sit between the speakers. Did it sound real? With direct comparison walking back to the other room, it didn't. The singer didn't sound as "clean" or "dry." I think that a lot of it stemmed from close miking a woman in an acoustically live room, and playing the captured signal, which was not representative of the entire soundfield, into an acoustically dead room, with two speakers. Maybe it would have been better to use just one speaker and put it up off the floor somewhat. Not bad though, and far from embarassing.

[soundminded]

You're kidding right? We did a lot of testing with human voice at KEF. It was an extremely revealing test within its bandwidth (and widely acknowledged by BBC Engineering as most difficult to reproduce). We actually did some "Live vs. Recorded" with some of us recorded in the anechoic chamber. (B&K mic., Sony PCM F-1) One thing we found was that level matching typically meant listening at a much lower level than you would normally have guessed.

We spend our lives talking and listening to others (at least some of us listen) and we are very discerning about the naturalness of human voice, even of people we haven't met.

The human voice is relatively easy to reproduce accurately in an anechoic chamber if you are only going to listen to it at one angle with respect to the loudspeaker. The giveaway will usually be the explosive parts of speech such as sibilants which contain the most high frequency energy. Even though a real human voice has a relatively narrow angle of radiation of these sounds, say 120 to 150 degrees, the difference between the balance of these sounds on and off axis with narrow radiating tweeters should be easy to hear. For example, if the speaker is equalized to high accuracy on axis, it should begin to sound detectably muffled say no more than 30 to 45 degrees off axis. By 60 degrees the difference should be easily heard even in an anechoic chamber. In a real room, the problem gets much worse because of the reflections of off axis radiation of the speaker system at low frequencies. The typical male voice has a fundimental frequency somewhere in the range of around 120-130 hz while the female voice is around 170-180 hz. Of course as with any recording, it is important to avoid proximity effect or the recording has to be carefully equalized to eliminate it. (This was one question I had about Atkinson's measurements of AR303 Zilch posted a link to in one of the closed threads. The microphone for measuring the woofer was placed so close to it from Atkinson's description, the woofer came within a hair's breath of touching it. One would expect at least some proximity effect under such measuring conditions no matter what the pickup pattern of the microphone but Atkinson never even mentioned it. Does that explain the 5 db peak in the bass before falloff or is that actually a characteristic of that speaker or that particular sample, that is was underdamped? I think Villchur put his speakers in a hole in the ground and suspended the microphone one foot or was it one meter above it.) I have found that it is almost always impossible to precisely reproduce the tonality of the female soprano voice with a direct firing speaker system no matter how carefully equalized. The sole exception so far has been the AR2ax placed catty corner at 45 degrees in the corners of a 12 x 15 room with large open arches on both sides. You can't get more than 45 degrees off axis in this arrangement.

We had 8 string players here today in a room of about 7500 cubic feet. This included two cellists (they are usually here every Sunday.) I know of no loudspeakers anywhere that could match their sound. Each instrument is nearly an omnidirctional radiator in all planes and the room acoustics are slightly on the live side. Needless to say they make a very pleasing sound...when they don't play wrong notes

I've been listening to the Amadeus Quartet's recording of the Trout Quintet on DG 449-746-2 made in Finland in 1975 and originally released as an LP. Taking the Bose 901's 18 db boost into consideration it requres a total of 51 db of boost at 30 hz with respect to 1 khz to flatten the bass in my almost 2000 cubic foot room. At that level, the double bass is well reproduced. The strings were excellent but the piano was remote and its high frequency content lacking making the recording less than totally satisfying (Howard did you review this recording?) There are also a surprising number of unwelcome low frequency disturbances in it. This is not as uncommon as you'd think even on cds but will ususlly not manifest itself on sound systems that don't have adequate gain at very low frequencies (the same thing happens with AR9 and I'd bet with Howards Velodyne subwoofer.) You have to choose between putting up with it or compromising the deepest bass. Without a sharp low frequency cutoff, use of a turntable in that room is impossible due to acoustic feedback, even for my well suspended Empire 698.

[speaker dave]

Of course as with any recording, it is important to avoid proximity effect or the recording has to be carefully equalized to eliminate it. (This was one question I had about Atkinson's measurements of AR303 Zilch posted a link to in one of the closed threads. The microphone for measuring the woofer was placed so close to it from Atkinson's description, the woofer came within a hair's breath of touching it. One would expect at least some proximity effect under such measuring conditions no matter what the pickup pattern of the microphone but Atkinson never even mentioned it. Does that explain the 5 db peak in the bass before falloff or is that actually a characteristic of that speaker or that particular sample, that is was underdamped?

Omni mics are used because they don't have any proximity effect. A B&K omni will come with a calibration curve for pressure response (as driven with the transducer and mic capsule sharing the same small enclosure), and they will be dead flat from below 20 to above 10k, depending on diameter. The LF rise on many systems when a nearfield curve is taken is the true 2pi response of the system. Most designers strike some sort of compromise between 2 pi flat and 4 pi flat, which will give some amount of rise when measured near field. If I recall the AR-1 was similarly a little underdamped with a Q slightly greater than 1.

We had 8 string players here today in a room of about 7500 cubic feet. This included two cellists (they are usually here every Sunday.) I know of no loudspeakers anywhere that could match their sound. Each instrument is nearly an omnidirctional radiator in all planes and the room acoustics are slightly on the live side. Needless to say they make a very pleasing sound...when they don't play wrong notes

You are very fortunate to have live music in your home!

David

[soundminded]

Omni mics are used because they don't have any proximity effect. A B&K omni will come with a calibration curve for pressure response (as driven with the transducer and mic capsule sharing the same small enclosure), and they will be dead flat from below 20 to above 10k, depending on diameter. The LF rise on many systems when a nearfield curve is taken is the true 2pi response of the system. Most designers strike some sort of compromise between 2 pi flat and 4 pi flat, which will give some amount of rise when measured near field. If I recall the AR-1 was similarly a little underdamped with a Q slightly greater than 1.


You are very fortunate to have live music in your home!

David

I think you have much more confidence in Atkinson's measurements, assessments, and conclusions than I do. I wonder just how omnidirectional a microphone is when the source is two inches away.

As music is an event in time, all comparisons are based on memory, even rapid fire AB switching between one element and another in what is meant to be a direct comparison. The frequent ability to have absolute live referenced to compare to assuming the goal of high fidelity is to produce the same or similar sounds is both convenient and it seems to me practically indespensible. Where there is a discrepency between what is measured and what is heard, in this particular case it is the measurement that is most suspect IMO. Sometimes it may be the equipment but often it is the methodology that is flawed. This results from the underlying model being an inaccurate representation of what is happening.

I've had many occasions to hear live concerts and I'm always struck by the profound effect the acoustics of venue have. As I've said, IMO not only is the ability of sound recording reproducing systems given the current state of the art far short of the ability to reproduce these acoustical effects, so is basic understanding of the science of acoustics itself.

It was interesting that in the evaluations of speakers B&K presented in the paper Ken cited (thank you Ken) called "Relevant loudspeaker tests in studios in Hi-Fi dealers' demo rooms in the home etc.,
— using 1/3 octave, pink weighted, random noise" B&K used the same rationale for high end rolloff related to the steady state acoustic response measured in Concert halls Villchur and BBC used. Looking at the FR curves, so did the manufacturers evidently. I've explained in the past why I think that is a mistake. Zilch, you have claimed in the past that the playback room acoustics play little or no role in perceived sound from loudspeakers. This paper seems to point to strong evidence that exactly the opposite is true. How do you explain it? Also Geddes and others seem to me to say that this effect is unimportant below certain frequencies yet the experienced (measured) FR especially in small rooms looks like a roller coaster ride and the variations from one room to another for the same speaker looks to be as great or greater than from one speaker to another in the same room. Care to offer an opinion?

BTW, 51 db of bass boost at 30 hz for Bose 901 was no typo. The comparable boost for AR9 for that recording is only in the range of 20 db. At 30 hz, AR9 is relatively a thousand times as efficient. The AR9s are in a room that is about 4000 cubic feet with a footprint of about 29-6 x 13-8. The 901s are in a room approximately 14 x 14 with a cathedral ceiling. Both have extensive glass windows and low pile carpeting or rugs.

[speaker dave]

I think you have much more confidence in Atkinson's measurements, assessments, and conclusions than I do. I wonder just how omnidirectional a microphone is when the source is two inches away.

Yes, I probably do. Again an omni mic. has no proximity effect. You can bring it up to near contact and see no effect at LF. I've done it many times.

It was interesting that in the evaluations of speakers B&K presented in the paper Ken cited (thank you Ken) called "Relevant loudspeaker tests in studios in Hi-Fi dealers' demo rooms in the home etc.,
— using 1/3 octave, pink weighted, random noise" B&K used the same rationale for high end rolloff related to the steady state acoustic response measured in Concert halls Villchur and BBC used. Looking at the FR curves, so did the manufacturers evidently. I've explained in the past why I think that is a mistake. Zilch, you have claimed in the past that the playback room acoustics play little or no role in perceived sound from loudspeakers. This paper seems to point to strong evidence that exactly the opposite is true. How do you explain it? Also Geddes and others seem to me to say that this effect is unimportant below certain frequencies yet the experienced (measured) FR especially in small rooms looks like a roller coaster ride and the variations from one room to another for the same speaker looks to be as great or greater than from one speaker to another in the same room. Care to offer an opinion?

They offer no evidence other than Moller prefers a system that he personally designed, which followed the curve. As always we are confusing steady state measurements made with non-directional microphones with the perceived response from human hearing and processing in a live room. As you move to a larger and larger room the steady state measured response of a system tends to have more and more extreme rolloff at HF yet it may still sound flat. Numerous papers, that I have referenced in the past, all point to the notion that the room has little effect above 200Hz in the perceived frequency response. Measurements don't automatically equal perception.

Toole writes about the variable of the room vs. the variable of the speaker. He finds that when speakers are compared within a room the room effect is stationary and evaluations are ranked based on the speaker performance. He did find that the room could become a variable, but only when a system was binaurally recorded in a number of rooms and the rooms could be A-B ed with instantaneous switching. In other words the ear got used to the room it was in.

[speaker dave]

Your comments about recording on stage in any enclosed space are simply are wrong. There would always be double reverb, with the reflections impacting the tail part of any signals that are recorded by any accent microphone placed to receive a simulation of the full-field output of the instrument. It is easy to prove my point: just listen to a variety of commercially made symphonic or small classical ensemble music recordings that have not been diddled with by electronic reverb machinery. (Several elite labels work or used to work this way.) The sense of hall space and ambiance is always picked up by the microphones, even when placed close up, which is why such accent microphone inputs have to be treated carefully. For additional data, just pick up a copy of any of several books recording engineer John Eargle has written where he deals with hall-sound issues.

I'm not totally convinced that the "double reverberation" issue is totally exclusive of a good end result. Over and over you discuss how the Allison speakers are superior because they create a spaciousness by involving the home listening room. Clearly it must be a good thing to have reverberation in a recording and then add reverberation on top, from the home listening room. Zilch's approach would lessen the double reverberation but that clearly isn't what you want.

I wonder if the ear isn't relatively okay with mixed reverberation, even though a small room and large room would clearly have clues to their room size, different arrival times for all of the reflections?

Zilch, there is a big difference between the wildly pan-potted, multi-microphone techniques used by engineers who deal with pop music and are not interested at all at simulating a live-music space, and the more purist techniques used by the top-tier engineers who record large and small classical ensembles.

I spoke with John Eargle about this a couple of times and he believed in multiple mics and a bit of pan-potting, as long as it was done subtly. He found purist approaches on their own, too limiting.

[soundminded]

Yes, I probably do. Again an omni mic. has no proximity effect. You can bring it up to near contact and see no effect at LF. I've done it many times.


They offer no evidence other than Moller prefers a system that he personally designed, which followed the curve. As always we are confusing steady state measurements made with non-directional microphones with the perceived response from human hearing and processing in a live room. As you move to a larger and larger room the steady state measured response of a system tends to have more and more extreme rolloff at HF yet it may still sound flat. Numerous papers, that I have referenced in the past, all point to the notion that the room has little effect above 200Hz in the perceived frequency response. Measurements don't automatically equal perception.

Toole writes about the variable of the room vs. the variable of the speaker. He finds that when speakers are compared within a room the room effect is stationary and evaluations are ranked based on the speaker performance. He did find that the room could become a variable, but only when a system was binaurally recorded in a number of rooms and the rooms could be A-B ed with instantaneous switching. In other words the ear got used to the room it was in.

"As you move to a larger and larger room the steady state measured response of a system tends to have more and more extreme rolloff at HF yet it may still sound flat. Numerous papers, that I have referenced in the past, all point to the notion that the room has little effect above 200Hz in the perceived frequency response. Measurements don't automatically equal perception"

My expience is exactly the opposite. Using a digital signal processor which is part of an experimental simulation prototype, the relative rate of high frequency decay compared to mid frequency decay and therefore the steady state spectral balance of the reverberant field is adjustable. Even a 10% change (the increments available) is clearly audible.

It's interesting that audiophiles who claim to be able to hear the differences from one wire to another, one wall outlet to another, even reverse of absolute polarity cannot detect many of the gross difference I can hear.

[Zilch]

Zilch, you have claimed in the past that the playback room acoustics play little or no role in perceived sound from loudspeakers.

The Toole/Olive work demonstrates listener preference rating of the speakers under evaluation to be independent of the room, indicating that we "hear through" it, whereas common wisdom instead attributes prime, indeed, dominant, significance to the room. It's the "shopping mall" thing: perceived spectral balance (and timbre) do not change with the space; we know who's talking to us -- mom is easily identifiable from anywhere in the grocery store, the parking lot, or inside the car berating us for wandering off. Outdoors or in, a clarinet is a clarinet, and I doubt anyone familiar with the differences between good and bad ones requires a particular space in which to make that determination.

In "small" rooms, typical of home listening spaces, studies define the variables more precisely, and indeed find that cues for localization, spectral balance, and spaciousness are functions of delay. Linkwitz says 6ms, Geddes says 10ms, Kantor and Toole, 20 ms, and Allison, 30 ms. It's not brick walls, rather, different psychoacoustic continua for the three characteristics. Geddes cuts to the bottom line and keys on the conclusion common among all of these: very early reflections (VER) are inherently detrimental -- avoid them, design speakers and deployments which do not generate them, and gain the benefits of taking control AWAY from the room in the region of frequencies above the modal transition zone. That accomplished, the listener may adjust the balance between imaging and spaciousness virtually independent of the listening space, according to taste, without affecting the spectral balance....